Well, at first I thought you were employed by a record store. I'm glad to help a little bit. In that case, you're employed and I'm not employed, so I'm not happy to help a lot.

Next I thought you are a student because I'm sure I saw
#fill in the rest of the function
in a few of the routines. Doing homework for other people is an ethics violation. Although, again, I err on the side of answering homework questions because examples of working code seem better than examples of bad algorithms. And since I write doctests into many of my posts, and try them before I post, for the most part I'm posting somewhat functional algorithms. Sometimes I understand the questions and answer accordingly.

Your xml isn't always about audio recordings. Maybe you're not a music store employee. The xml questions have been long running and have not changed much. It seems like a class would advance faster. So perhaps you're not a student, either. I'm baffled. But I also don't feel like answering more xml questions. I've now explored the xml module and have learned enough about it that I've lost personal motivation to answer more of these questions.